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Thread: sampan building questions.

  1. #1
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    Default sampan building questions.

    Bear with me on this.

    I am building a thirty foot sampan trying to use traditional plank joining.
    this means that (as far as my research has shown) the planks are pegged edge to edge with bedding compound between them. I have wood ordered but i think i will have a bit of ripping to do since i am not at all sure of how wide the planks need to be to fit the curves of this hull. The plans are for a 15 foot and i lofted them to thirty because 15 is just not very useful for what i want to do. (stolen from the cheap pages) and yes i do now own the plans.

    http://freepages.genealogy.rootsweb....ke_Sampan1.jpg




    http://freepages.genealogy.rootsweb....ke_Sampan2.jpg


    since i have never done this particular type of construction I am a bit unsure of some of the detail's.

    thanks in advance and i am sure i will have several thousand more questions.

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    Default Re: sampan building questions.

    It depends on how thick your stock is, how much backing out you need to do on the inside, and how much flogging off outside, to finish at the correct thickness. The area co consider most is the tight turn at the bilge, so you can go quick out (wide plank), slowly round (narrow) and quick up.

    How did you calculate the scantlings to suit the big increase in size?
    It really is quite difficult to build an ugly wooden boat.

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    Default Re: sampan building questions.

    Quote Originally Posted by Peerie Maa View Post
    It depends on how thick your stock is, how much backing out you need to do on the inside, and how much flogging off outside, to finish at the correct thickness. The area co consider most is the tight turn at the bilge, so you can go quick out (wide plank), slowly round (narrow) and quick up.

    How did you calculate the scantlings to suit the big increase in size?
    well from the look she really has no tight turns to the bilge at least not as tight as some i have done. I am going with 1" 5/8th inside planed planking that gives me 5/8" to play with. I had figured to reduce the width in the turn but one consideration is how the boat will look with wide verses narrow plank. I want to finish some of it bright.

    as for the scantlings I am going 2"X6" floors and frames in my lumber order on the thirty foot. which is very much larger than it needs. there really is not much to this sampan mostly it is hull and bulkheads.

    The way i am going to make that judgment is that i am going to build one directly off the plans as Blake drew them up in china off the hull. Blakes drawing is of a 15 foot boat. then I will make the scantling decision. There really is no better option since these where never made from a paper plan.

    this is somewhat the difficulty with trying to build in the traditional methods because almost all I have been able to find is conjecture. I am going to have to noodle my way around, trying to forget the western boat building model. I have managed this with skin on frame construction and now i want to try something a bit different.

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    Default Re: sampan building questions.

    Great looking boat and fun project. Keep asking questions and coming up with answers. Make it work.

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    Default Re: sampan building questions.

    I'm not sure if you plan to Junk rig her but you might find some interesting info/help through the JR forum.
    http://groups.yahoo.com/group/junkrig/
    My take is that if you poke someone with a sharp stick they'll get annoyed, if you smile and shake their hand they will be your friends.

    John Welsford

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    Default Re: sampan building questions.

    Oh ya I love my junk rig
    thanks for the link

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    Default Re: sampan building questions.

    My research has shown you're out of your mind.

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    Default Re: sampan building questions.

    was in my mind once JimD, got boring after a while. so i went wandering.
    I think i like it better out here.

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    Default Re: sampan building questions.

    Quote Originally Posted by 2MeterTroll View Post
    was in my mind once JimD, got boring after a while. so i went wandering.
    I think i like it better out here.
    So seriously, you are just doubling all the linear measurements and are gonna somehow figger out how to trunnel it all up into a boat? It won't be boring when it falls apart on you. Built lots of other boats by other means, I presume?

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    Default Re: sampan building questions.

    ah
    no JimD i am not just stretching the boat to thirty feet. the width, length, free board, internal volumes, center of gravity turn of the bilge, rocker, bulk head placement, &c. all have to be figured you also have to think the weight out and reposition the mast and dagger board, floors, rails, decks, how the whole boat will Interact with the water air interface. water lines, prime and secondary stability factors in the average weather conditions as well those that fall outside the norm. then figure where all the stuff goes that you are required to have.
    the only real magic trick is that i am going to do it in my head and hands.

    The 15 foot directly off the line plan will be the model because only a fool would try to nail all this down with out seeing how this hull will flex, twist, bend, pound, roll, warp, and all the other things boats do when under way.

    I guess i am out of my mind

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    Default Re: sampan building questions.

    If you need any photos of working sampans, let me know! Rick

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    Default Re: sampan building questions.

    Rick i would love photos of working sampans

    close ups of various boat bits would be good to while i am dreaming.
    Thanks in advance.

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    Default Re: sampan building questions.

    I keep threatening to junk rig one of my little plywood boats. Perhaps this year I'll get around to it. Got a sail plan in mind, 2MT ?

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    Default Re: sampan building questions.

    Rick i would love photos of working sampans
    OK I'll trawl through the photo collection and see what I can find. Rick

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    Default Re: sampan building questions.

    yep the 15 foot will have a single stick as drawn with a little rake to it. six panel junk rig. I am figuring about 8' X 12' about 90 sq foot of area kinda large but easy enough to reef if i need to. and if its to small i can add a panel. I like the fuller rounded style of sail with the high rake to the upper battens. I might double sheet this one because the sheets can get hung on the battens at times

    I might make another sail in the dragon wing configuration just to see if i can and how a wing sail works.

    the 30 foot I figure two sails a main and fore to cut the weight of the main down a bit.

    I love the junk rig.... mostly cause i am lazy i see no need to jump up and run around doing this and that when all i have to do is move the tiller

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    Default Re: sampan building questions.

    Quote Originally Posted by 2MeterTroll View Post
    ... I like the fuller rounded style of sail with the high rake to the upper battens. I might double sheet this one because the sheets can get hung on the battens at times


    the 30 foot I figure two sails a main and fore to cut the weight of the main down a bit.

    I love the junk rig.... mostly cause i am lazy i see no need to jump up and run around doing this and that when all i have to do is move the tiller
    Love the junk, too. Especially the low aspect fan shape, double sheeted. But keep in mind on a small, narrow hull you might have a hard time sorting things out so the sheets can be long enough unless you make the panels very narrow, meaning lots of battens. And a jib on a well canted mast in the bow looks so cool. Not sure what this oddball is:



    Bigger


  17. #17
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    Default Re: sampan building questions.

    Have you read this book? I have not:



    Although I have designed a few junk sails from the Hasler/McCloud book.


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    Default Re: sampan building questions.

    If I were considering a 30 footer I would be looking at a deeper, tubbier hull design such as:




    http://images.google.ca/imgres?imgur...N%26start%3D20

    rather than the lines you have chosen which will result in something more like a big skiff.

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    Default Re: sampan building questions.

    Thanks JimD yep i have read those books and practically everything i could find on the net in both English and Chinese.

    I picked the blake design because the thirty foot will be purpose built. and a tubbier hull wont work for what it will be doing. the idea is to cut my teeth on a couple sampans and then do a 50 foot junk. that is in the future so i am just looking at hulls now and not doing to much dreaming.

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    Default Re: sampan building questions.

    First off, stretching a fifteen foot punt to a thirty foot boat isn't going to translate very well at all. It's not a direct proportion. You're going to have weight and stability issues to work out, big time. Additionally, there is a world of engineering difference between sampans and junks. It's not just a matter of size.

    As for your caulking question, yes, the planks are set edge to edge with tenons, sort of like bisquit joinery. The caulking is made up of oakum like hemp fibre and seeds, which supposedly swell a lot and close up the seams. Good luck ordering marijuana seeds from WestMarine!

    That said, Asian boat construction is, like Asian writing, completely indecipherable to the uninitiated. Deceptively simple, but the devil's in the details. If you are really serious about this, plan on a LONG learning curve. There aren't a lot of Asian boatbuilders around here you can seek out for help.

    But, if you must, check out the San Francisco Maritime Historical Park. http://www.nps.gov/archive/safr/more_junk.html



    They're the only ones I know of who have attempted to traditionally build a junk recently in the US. She's at the Hyde Street Pier in SF. The "Grace Quan" is a replica of SF Bay shrimping junks which were active in the late 1800's and early 1900's when there was a large Chinese shrimping industry on the Bay. She's built of redwood, surprisingly, as were the originals.



    If I were you, I wouldn't even consider building any sort of Asian small craft by traditional methods without obtaining and studying carefully, "Junks and Sampans of the Yangtze River" by George R.G. Worchester. Worchester was a British Customs agent in the twenties and thirties and extensively cataloged Chinese junks and sampans, much in the same way that Howard Chapelle and the WPA Historic Merchant Marine Survey did here in the US. This large book (actually three volumes in the original printing), it may cost you several hundred dollars, but it is essential. It is the only known complete compendium with complete plans, scantlings, construction techniques and so on covering all the various types, small and large. If you are lucky, you may find a copy of the 1970's reprint by the Naval Institute Press for somewhere around $300 or $400. Sorry, but ya gotta have it or you're just pissing in the wind.
    Last edited by Bob Cleek; 03-09-2009 at 01:04 PM.

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    Default Re: sampan building questions.

    Bob you are the second person who has warned me about just stretching the boat. Thank you.
    I am not just stretching the boat and hopeing. i have been working on sizing that sampan for 5 months at least an hour a day, every day. I have just not figured the scantlings because I think that sailing a smaller one will give me the data i need to make the correct decisions when i do. I know it will be a long learning curve because i have to learn a different way of thinking about how boats are built. i have done this in several other arenas already. this is a new challenge. for me this is a continuation of a course i set several years ago.

    I live in oregon, hemp seeds are not a problem... LOL. however I am not opposed to epoxy or 5200 just like SOF boats there are places that you depart from tradition because the materials are no longer get able or what we use now is by far the better choice.

    It is costing me several hundred Bob and I agree with you. I have read it and will be owning a copy soon. (the bloody book is on order; till it gets in my hands i am borrowing a copy)
    I have spent ten years in research and figure to spend several more in building. my one advantage is i live in Portland and may have some access to Chinese boat builders through the community here. the lynch pin is getting them to talk to me and the only way i know to do that is to put a boat in the water that shows i am serious. (we have a community here around dragon boating and several of those have been made by the chinese folks here but they didn't come out till a boat was actually on the water)
    I don't speak Chinese what i do speak is sailor and fishermen. both of those languages are spoken with the hands.

    I regards to pissing in the wind; I don't like wet pant legs.
    Last edited by 2MeterTroll; 03-09-2009 at 01:52 PM. Reason: saying something else

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    Default Re: sampan building questions.

    I am asking questions here because there is more boat building experiance in this one place than any number of books on the subject. Please don't think i am being flip when i answer a question or a point.
    I have read everything i could get my hands on about building junks and sampans; as was said the devils are in the details and i am hunting those devils.

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    Default Re: sampan building questions.

    Good luck ordering marijuana seeds from WestMarine!
    As a BCer how could I resist :

    https://www.miraclesource.com/cart.p...FRBbagodxhFTZg

    $8.99 lb ;they ship to the States too

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    Default Re: sampan building questions.

    he he he he thanks Gert

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    Default Re: sampan building questions.

    2MT, Join the JR forum and go to Files and look at Arne's articles on building sails with camber. His writings are worth their weight in gold.
    My take is that if you poke someone with a sharp stick they'll get annoyed, if you smile and shake their hand they will be your friends.

    John Welsford

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    Default Re: sampan building questions.

    Bob, I sold a copy of Junks of the Yangtze today for $100. You can find a copy without a dust jacket for that (I don't have another copy, except my own.)

    William Maxwell Blake didn't show a junk rig for that particular design, just a lug rig with spars at top and bottom. As for edge fastening, they've got this stuff called strip planking...

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    Default Re: sampan building questions.

    nope just a single stick the rig i am taking off of some 1940s pictures of this style boat.
    however i am not at all sure how accurate the photos are of what they really used. hongkong being slightly touristy at the time

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    Default Re: sampan building questions.

    When I was in Hong Kong in the 1960s, there were still sailing fishing boats. Of course, Blake was in Singapore, and rigs there may have differed.

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    Default Re: sampan building questions.

    Rick i would love photos of working sampans
    Sorry, couldn't get to this yesterday and I'll be away for the next few days. I'll dig out the photos on the weekend. The pictures I have are all of current boats in Vietnam. They don't sail anymore, they all have engines, so they'll be of no help re rigging. Rick

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    Default Re: sampan building questions.

    Rick NO problem at all. ive got time.

    JohnW have run into so many different rigs from china that i just finally picked the one i like that works at sea.

    Thank you all for the input and please keep it coming.

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    Default Re: sampan building questions.

    Ok, 2meter, if you've heard of the book and you've ordered a copy, then you've passed the first part of the test. LOL

    Now, my next question is this: I understand that you've spend a lot of time at the drawing board working on this boat... BUT... and I've asked this of everybody I have ever met who attempted to design their own boat who wasn't in the boat designing business to begin with...

    Do you really think you can design a better boat as an amateur... or, as here, as has evolved in use by highly experienced mariners over centuries?

    I find it hard to imagine that you wouldn't find close to exactly the boat you want and need... i.e. right size, right hull for the waters you plan to sail, and all the rest, in Worchester's book. You would know you were building a proven pedigreed design. You wouldn't risk building a cranky boat or ending up with something you couldn't give away when you were done with her. "I designed and built it myself" is NOT a big selling point. "It's an historic replica of a whatever...." on the other hand, IS a big selling point and will make your boat a very interesting and valuable artifact.

    Just a thought. Remember, the sea has a way of humbling the proudest of men.

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    Default Re: sampan building questions.

    Quote Originally Posted by Bob Cleek View Post
    Ok, 2meter, if you've heard of the book and you've ordered a copy, then you've passed the first part of the test. LOL

    Now, my next question is this: I understand that you've spend a lot of time at the drawing board working on this boat... BUT... and I've asked this of everybody I have ever met who attempted to design their own boat who wasn't in the boat designing business to begin with...

    Do you really think you can design a better boat as an amateur... or, as here, as has evolved in use by highly experienced mariners over centuries?
    ok im gonna deal with this in two parts because I think this is a most fair question.
    1. do i think i can build a better boat than a professional boat designer of today? Yes i do! hands down.

    2. than the highly experienced mariners that conceptualized and built these boats? No! all i can do is hope to stand on their shoulders.

    I find it hard to imagine that you wouldn't find close to exactly the boat you want and need... i.e. right size, right hull for the waters you plan to sail, and all the rest, in Worchester's book. You would know you were building a proven pedigreed design. You wouldn't risk building a cranky boat or ending up with something you couldn't give away when you were done with her. "I designed and built it myself" is NOT a big selling point. "It's an historic replica of a whatever...." on the other hand, IS a big selling point and will make your boat a very interesting and valuable artifact.

    Just a thought. Remember, the sea has a way of humbling the proudest of men.
    Bob I have looked for ten years for exactly what i need to do the job. the whole job from how much wood it uses to how high up a river it can go, what kind of rapids it can take and how big of seas it will handle to what the boat will look like. i have looked at dory's, drifters, sleds, umiaks, kayaks, canoes, prams, small sloops, old river boats, pe-roes (sp), plugs, multi hulls, cat boat, beetles, on and on and on. if i can figure out how to post a picture on this site i will show you the contenders in the final cut. most of those small boats i have either built or i have found someone who has had the boat and taken a ride or six in it.

    I don't take it lightly that i am going to enlarge a boat and i really appreciate that you are asking this kind of question. it makes my rethink my motivations and what i want the boat to do.

    finally: the sea rewards those who are humble and work within her rules.

  33. #33
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    Default Re: sampan building questions.

    Your statement about taking the boat up the river reminds me of an event that's supposed to have happened twice in Vietnam's history, many centuries ago. The Vietnamese army defending itself from Chinese invasion, enticed the Chinese fleet of fairly large craft up the river (I could look up the names etc. but it's a river near Hai Phong, part of the Red River delta) at high tide. The Vietnamese had buried sharpened stakes in the mud right across the river, so that when the Chinese fleet tried to sail back down the river, the boats were impaled on the stakes and, of course, the Vietnamese won a famous victory. The records do show that this happened twice, with a gap of a couple of centuries or more. There's a very dramatic rendition of one of these events in a very large painting in Ha Noi's aptly named History Museum. Not a lot of red uniforms (Viet) floating in the river in that painting but, of course, lots of blue ones! Rick

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    Default Re: sampan building questions.

    I live in oregon its kinda like NZ only with more trees. I no longer do oil exploration or king crabbing. how the heck am i going to afford to go hang out in Vietnam looking around a museum?
    this is why man learned to build boats.

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    Default Re: sampan building questions.

    Quote Originally Posted by 2MeterTroll View Post
    ok im gonna deal with this in two parts because I think this is a most fair question.
    1. do i think i can build a better boat than a professional boat designer of today? Yes i do! hands down.

    2. than the highly experienced mariners that conceptualized and built these boats? No! all i can do is hope to stand on their shoulders.



    Bob I have looked for ten years for exactly what i need to do the job. the whole job from how much wood it uses to how high up a river it can go, what kind of rapids it can take and how big of seas it will handle to what the boat will look like. i have looked at dory's, drifters, sleds, umiaks, kayaks, canoes, prams, small sloops, old river boats, pe-roes (sp), plugs, multi hulls, cat boat, beetles, on and on and on. if i can figure out how to post a picture on this site i will show you the contenders in the final cut. most of those small boats i have either built or i have found someone who has had the boat and taken a ride or six in it.

    I don't take it lightly that i am going to enlarge a boat and i really appreciate that you are asking this kind of question. it makes my rethink my motivations and what i want the boat to do.

    finally: the sea rewards those who are humble and work within her rules.
    My wife who is a very nice person and does lots of English to English translation says i need to explain the answer to question number one.

    Ok it goes like this. I pay a marine architect or if you will a boat designer to check my numbers and give suggestions.
    I wont pay to design a boat from scratch.

    The reason i don't go in with hat in hand and have some other person design me a boat, is the boat I want is in my head. No matter how well the explanation of the boat in my head is done the boat designer has his own idea's and those will color any design he does.
    Since i don't want the boat he has in his head the responsibility of doing the design is mine.
    Am i better at designing my boat? yes.
    Am I better at designing his boat? no.
    Am i better at designing boats in general? no.

    Modern designers do good work they are worth the money.
    I pay them to do what they are trained to do. I just don't pay them to do my thinking for me.

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